Linux命令——yum

翻译自：20 Linux YUM (Yellowdog Updater, Modified) Commands for Package Management

前言

本篇文章将介绍如何使用RedHat开发的YUM（Yellowdog Updater Modified）工具，在Linux系统上安装，更新，删除，查找，管理软件包和软件仓库。

yum简介

yum，是Yellow dog Updater, Modified 的简称，是杜克大学为了提高RPM 软件包安装性而开发的一种软件包管理器。起初是由yellow dog 这一发行版的开发者Terra Soft 研发，用python 写成，那时还叫做yup(yellow dog updater)，后经杜克大学的Linux@Duke 开发团队进行改进，遂有此名。yum 的宗旨是自动化地升级，安装/移除rpm 包，收集rpm 包的相关信息，检查依赖性并自动提示用户解决。yum 的关键之处是要有可靠的repository，顾名思义，这是软件的仓库，它可以是http 或ftp 站点，也可以是本地软件池，但必须包含rpm 的header，header 包括了rpm 包的各种信息，包括描述，功能，提供的文件，依赖性等。正是收集了这些header 并加以分析，才能自动化地完成余下的任务。

yum 的理念是使用一个中心仓库(repository)管理一部分甚至一个distribution 的应用程序相互关系，根据计算出来的软件依赖关系进行相关的升级、安装、删除等等操作，减少了Linux 用户一直头痛的dependencies 的问题。这一点上，yum 和apt 相同。yum 可以同时配置多个资源库(Repository)，简洁的配置文件（/etc/yum.conf），自动解决增加或删除rpm 包时遇到的依赖性问题，保持与RPM 数据库的一致性。

yum命令使用示例

使用YUM安装包

要安装名为Firefox 14的软件包，只需运行以下命令，它将自动查找并安装Firefox所需的所有依赖项。

# yum install firefox
Loaded plugins: fastestmirror
Dependencies Resolved

================================================================================================
 Package                    Arch        Version                    Repository            Size
================================================================================================
Updating:
firefox                        i686        10.0.-.el6.centos     updates              M
Updating for dependencies:
 xulrunner                     i686        10.0.-.el6.centos     updates              M

Transaction Summary
================================================================================================
Install        Package(s)
Upgrade        Package(s)

Total download size:  M
Is this ok [y/N]: y
Downloading Packages:
(/): firefox-10.0.-.el6.centos.i686.rpm                                |   MB   :
(/): xulrunner-10.0.-.el6.centos.i686.rpm                              |   MB   :
------------------------------------------------------------------------------------------------
Total                                                            kB/s |   MB   :

Updated:
  firefox.i686 :10.0.-.el6.centos

Dependency Updated:
  xulrunner.i686 :10.0.-.el6.centos

Complete!

在系统上安装任何软件包之前，上述命令将询问确认。如果要在不要求任何确认的情况下自动安装软件包，请使用选项-y，如下例所示。

yum -y install firefox

使用YUM删除包

删除包时，如果连依赖一起删除，只需要执行以下命令

yum remove firefox
Loaded plugins: fastestmirror
Setting up Remove Process
Resolving Dependencies
--> Running transaction check
---> Package firefox.i686 :10.0.-.el6.centos set to be erased
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================
 Package                    Arch        Version                        Repository            Size
====================================================================================================
Removing:
 firefox                    i686        10.0.-.el6.centos            @updates               M

Transaction Summary
====================================================================================================
Remove         Package(s)
Reinstall      Package(s)
Downgrade      Package(s)

Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing        : firefox-10.0.-.el6.centos.i686                                                                                                                          /

Removed:
  firefox.i686 :10.0.-.el6.centos

Complete!

同样，上面的命令会在删除包之前询问确认。要禁用确认提示，只需添加选项-y，如下所示。

yum -y remove firefox

yum remove有个弊端，例如yum remove -y vim，他只会匹配vim-xxx.rpm这个包，他的依赖包并不会被卸载。比如vim-minimal-7.4.160-4.el7.x86_64，必须单独写在才可以yum -y remove vim-minimal

使用YUM更新包

假设你有一个旧版本的MySQL，你希望将其更新为最新的稳定版本。只需运行以下命令，它将自动解决所有依赖项问题并安装它们。

# yum update mysql
Loaded plugins: fastestmirror
Dependencies Resolved

============================================================================================================
 Package            Arch                Version                    Repository                    Size
============================================================================================================
Updating:
 vsftpd             i386                2.0.-.el5_8.           updates                        k

Transaction Summary
============================================================================================================
Install        Package(s)
Upgrade        Package(s)

Total size:  k
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Updating       : vsftpd                                                                     /
  Cleanup        : vsftpd                                                                     /

Updated:
  vsftpd.i386 :2.0.-.el5_8.

Complete!

使用YUM列出包

使用list参数搜索具有名称的特定包。例如，要搜索名为openssh的包，使用命令

# yum list openssh
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.neu.edu.cn
 * epel: mirror.neu.edu.cn
 * extras: mirror.neu.edu.cn
 * rpmforge: mirror.nl.leaseweb.net
 * updates: mirror.nus.edu.sg
Installed Packages
openssh.i386                                       .3p2-.el5_6.                                                                      installed
Available Packages                                 .3p2-.el5   

为了使您的搜索更准确，请使用其版本定义包名称，如果你知道的话。例如，搜索包的特定版本openssh-4.3p2

# yum list openssh-.3p2

使用YUM搜索包

如果你不记得包的确切名称，请使用search参数搜索所有可用包以匹配你指定的包的名称。

# yum search vsftpd
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.neu.edu.cn
 * epel: mirror.neu.edu.cn
 * extras: mirror.neu.edu.cn
 * rpmforge: mirror.nl.leaseweb.net
 * updates: ftp.iitm.ac.in
============================== Matched: vsftpd ========================
ccze.i386 : A robust log colorizer
pure-ftpd-selinux.i386 : SELinux support for Pure-FTPD
vsftpd.i386 : vsftpd - Very Secure Ftp Daemon

使用YUM获取包的信息

假设您想在安装之前知道包的信息。要获取包的信息，只需发出以下命令。

# yum info firefox
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.neu.edu.cn
 * epel: mirror.neu.edu.cn
 * extras: mirror.neu.edu.cn
 * rpmforge: mirror.nl.leaseweb.net
 * updates: ftp.iitm.ac.in
Available Packages
Name       : firefox
Arch       : i386
Version    : 10.0.
Release    : .el5.centos
Size       :  M
Repo       : updates
Summary    : Mozilla Firefox Web browser
URL        : http://www.mozilla.org/projects/firefox/
License    : MPLv1. or GPLv2+ or LGPLv2+
Description: Mozilla Firefox is an open-source web browser, designed for standards
           : compliance, performance and portability.

使用YUM列出所有可用包

要列出Yum数据库中的所有可用包，请使用以下命令。

# yum list | less

使用YUM列出所有已安装的软件包

要列出系统上所有已安装的软件包，只需发出以下命令，它将显示所有已安装的软件包。

# yum list installed | less

找出文件属于哪个软件包

provides参数用于查找特定文件所属的包。例如，如果您想知道包含/etc/httpd/conf/httpd.conf文件的包名称。

# yum provides /etc/httpd/conf/httpd.conf
Loaded plugins: fastestmirror
httpd-2.2.-.el5.centos.i386 : Apache HTTP Server
Repo        : base
Matched from:
Filename    : /etc/httpd/conf/httpd.conf

httpd-2.2.-.el5.centos..i386 : Apache HTTP Server
Repo        : updates
Matched from:
Filename    : /etc/httpd/conf/httpd.conf

httpd-2.2.-.el5.centos.i386 : Apache HTTP Server
Repo        : updates
Matched from:
Filename    : /etc/httpd/conf/httpd.conf

httpd-2.2.-.el5.centos..i386 : Apache HTTP Server
Repo        : installed
Matched from:
Other       : Provides-match: /etc/httpd/conf/httpd.conf

使用whatprovides 效果是一样的

使用Yum检查可用更新

要查找系统上已安装的软件包有多少可用更新，请检查以下命令。

# yum check-update

使用Yum更新系统

如下命令将为系统安装所有最新补丁和安全更新。

# yum update

列出所有可用的Group Packages

在Linux中，若干个包可以捆绑到特定组。 你可以安装特定组（组中包的依赖会自动安装），而不是使用yum单个组内的软件包。 例如，要列出所有可用组，只需发出以下命令。

# yum grouplist
Installed Groups:
   Administration Tools
   DNS Name Server
   Dialup Networking Support
   Editors
   Engineering and Scientific
   FTP Server
   Graphics
   Java Development
   Legacy Network Server
Available Groups:
   Authoring and Publishing
   Base
   Beagle
   Cluster Storage
   Clustering
   Development Libraries
   Development Tools
   Eclipse
   Educational Software
   KDE (K Desktop Environment)
   KDE Software Development

安装Group Packages

要安装特定的软件包组，我们使用参数groupinstall。例如，要安装“MySQL数据库”，只需执行以下命令即可。

# yum groupinstall 'MySQL Database'
Dependencies Resolved

=================================================================================================
Package                                Arch      Version             Repository        Size
=================================================================================================
Updating:
 unixODBC                           i386      2.2.-.el5      base               k
Installing for dependencies:
 unixODBC-libs                      i386      2.2.-.el5      base               k

Transaction Summary
=================================================================================================
Install        Package(s)
Upgrade        Package(s)

Total size:  k
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing     : unixODBC-libs    /
  Updating       : unixODBC         /
  Cleanup        : unixODBC         /

Dependency Installed:
  unixODBC-libs.i386 :2.2.-.el5

Updated:
  unixODBC.i386 :2.2.-.el5

Complete!

更新Group Packages

使用参数groupupdate

# yum groupupdate 'DNS Name Server'

Dependencies Resolved
================================================================================================================
 Package            Arch            Version                Repository           Size
================================================================================================================
Updating:
 bind                           i386            :9.3.-.P1.el5_8.          updates               k
 bind-chroot                    i386            :9.3.-.P1.el5_8.          updates               k
Updating for dependencies:
 bind-libs                      i386            :9.3.-.P1.el5_8.          updates               k
 bind-utils                     i386            :9.3.-.P1.el5_8.          updates               k

Transaction Summary
================================================================================================================
Install        Package(s)
Upgrade        Package(s)

Total size: 2.0 M
Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Updating       : bind-libs            /
  Updating       : bind                 /
  Updating       : bind-chroot          /
  Updating       : bind-utils           /
  Cleanup        : bind                 /
  Cleanup        : bind-chroot          /
  Cleanup        : bind-utils           /
  Cleanup        : bind-libs            /

Updated:
  bind.i386 :9.3.-.P1.el5_8.                  bind-chroot.i386 :9.3.-.P1.el5_8.

Dependency Updated:
  bind-libs.i386 :9.3.-.P1.el5_8.             bind-utils.i386 :9.3.-.P1.el5_8.

Complete!

移除Group Packages

使用参数groupremove

# yum groupremove 'DNS Name Server'

Dependencies Resolved

===========================================================================================================
 Package                Arch              Version                         Repository          Size
===========================================================================================================
Removing:
 bind                   i386              :9.3.-.P1.el5_8.          installed           2.1 M
 bind-chroot            i386              :9.3.-.P1.el5_8.          installed           0.0

Transaction Summary
===========================================================================================================
Remove         Package(s)
Reinstall      Package(s)
Downgrade      Package(s)

Is this ok [y/N]: y
Downloading Packages:
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Erasing        : bind                                                   /
warning: /etc/sysconfig/named saved as /etc/sysconfig/named.rpmsave
  Erasing        : bind-chroot                                            /

Removed:
  bind.i386 :9.3.-.P1.el5_8.                                        bind-chroot.i386 :9.3.-.P1.el5_8.

Complete!

列出已启用的Yum仓库

要列出系统中所有已启用的Yum存储库，请使用以下选项。

# yum repolist

repo id                     repo name                                            status
base                        CentOS- - Base                                      enabled:  ,
epel                        Extra Packages for Enterprise Linux  - i386         enabled:  ,
extras                      CentOS- - Extras                                    enabled:
mod-pagespeed               mod-pagespeed                                        enabled:
rpmforge                    RHEL  - RPMforge.net - dag                          enabled: ,
updates                     CentOS- - Updates                                   enabled:
repolist: ,

列出所有已启用和已禁用的Yum存储库

# yum repolist all

repo id                     repo name                                            status
C5.-base                   CentOS-5.0 - Base                                    disabled
C5.-centosplus             CentOS-5.0 - Plus                                    disabled
C5.-extras                 CentOS-5.0 - Extras                                  disabled
base                        CentOS- - Base                                      enabled:  ,
epel                        Extra Packages for Enterprise Linux  - i386         enabled:  ,
extras                      CentOS- - Extras                                    enabled:
repolist: ,

从特定yum仓库安装包

要从特定的yum仓库（已启用或已禁用）安装特定软件包，必须在yum命令中使用-enablerepo选项。 例如，要安装PhpMyAdmin 3.5.2软件包，只需执行命令即可。

# yum --enablerepo=epel install phpmyadmin

Dependencies Resolved
=============================================================================================
 Package                Arch           Version            Repository           Size
=============================================================================================
Installing:
 phpMyAdmin             noarch         3.5.-.el6        epel                 4.2 M

Transaction Summary
=============================================================================================
Install        Package(s)

Total download size: 4.2 M
Installed size:  M
Is this ok [y/N]: y
Downloading Packages:
phpMyAdmin-3.5.-.el6.noarch.rpm                       | 4.2 MB     :
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : phpMyAdmin-3.5.-.el6.noarch             /
  Verifying  : phpMyAdmin-3.5.-.el6.noarch             /

Installed:
  phpMyAdmin.noarch :3.5.-.el6

Complete!

交互式yum shell

Yum提供自定义shell，可以在其中执行多个命令。

# yum shell
Loaded plugins: fastestmirror
Setting up Yum Shell
> update httpd
Loading mirror speeds from cached hostfile
 * base: mirrors.sin3.sg.voxel.net
 * epel: ftp.riken.jp
 * extras: mirrors.sin3.sg.voxel.net
 * updates: mirrors.sin3.sg.voxel.net
Setting up Update Process
>

清除Yum缓存

默认情况下，yum再/var/cache/yum及其子目录下保存已启用Yum仓库中的rpm包，要清除这些缓存下来的rpm包，需要定期运行以下命令来清理所有缓存并确保 没有什么不必要的空间正在使用。

# yum clean all

查看Yum历史

查看Yum命令的历史纪录

# yum history

Loaded plugins: fastestmirror
ID     | Login user               | Date and time    | Action(s)      | Altered
-------------------------------------------------------------------------------
     | root               | -- : | Install        |
      | root               | -- : | Install        |
      | root               | -- : | Erase          |     EE
      | root               | -- : | Install        |
      | root               | -- : | Install        |
      | root               | -- : | Install        |
      | root               | -- : | I, U           |    E<
      | root               | -- : | Install        |     >
      | root               | -- : | I, U           |   EE
      | System            | -- : | Install        |
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